Hoisting apparatus



Dec. 20, 1932. 1,891,883

F. E. STAHL HOISTING APPARATUS Filed July 30. 1930 3 Sheets-Sheet l lil. 71

EL .11 D 9 Snventor FRANKLS'TAH Dec. 20, 1932. F E STAHL HOISTING APPARATUS Filed July 30. 1930 5 Sheets-Sheet :aumentar BBQ? Dec. 20, 1932.

F. E. STAHL HOISTING APPARATUS Filed July 30. 1930 5 Sheets-Sheet I5 t is JTl @19.5.

y :inventor FRANK E. STAHL Wha/L0( WML/Q fw.; dtorneg5 Patented Dec. 20, 1932 -UNITED STATES PMI-:NT OFFICE FRANK E. STAHL, 0F TONA'WANDA, NEW YORK, ASSIGNOR TO THE OOLUIBUS- ICKINNON CHAIN CORPORATION, OF TONAWANDA, NEW YORK, A CORPORATION 0F NEW YORK HOISTD'G APPARATUS Application led July 30,

This invention relates to power hoists and especially electrically operated hoists, such as employ a cable or chain for the load carrying element.

An object generally of the invention is to provide improved apparatus whereby a brake is applied in lowering the cable or chain and released while hoisting a load. Other objects will appear from the disclosure herein.

In such apparatus the operating power circuit is provided with a manually controlled reversing circuit. In connection with such a control I employ a power circuit cut-out and a brake and means automatically actuated by the hoisting chain or cable and the manual control of the reversing switch whereby the brake is applied when the reversing switch is in neutral position in lowering the load but held released when a load is being` hoisted.

Y Each automatic operation throws the circuit ofi' and one of these applies the brake. Incidently the said meansv actuated by the cable or chain prevents improper operation of the manual control, that is to say, the workman cannot operate the reversing switch to cause the motor to produce a continuation of the upward or downward movement of the load after the load hook has reached the upward limit of its travel or downward respectively. In brief the limit of the upward and downward movement of the load is automatically fixed while braking action is applied in the downward movement only of the load.

The invention is embodied in the example herein shown and described.l the features of novelty being finally claimed.

Figure 1 is a front view of a hoisting means according to the invention with parts broken out and in section.

Fig. 2 is a sectional view taken horizontally on the line II Fig. 1 of one form of mechanism for translating the power of the motor shaft to the hoist sheave for operating the hoisting cha-in.

Fig. 3 is a vertical section on, say the line III-III of Fig. 1 looking to the left with the hoisting chain shown as broken out.

Fig. 4 is a vertical section on the line IV-IV 0f Fig. 1 looking to the left.

1930. Serial N0. 471,815.

Fig. 4l is an elevation showing the manual control for the reversing switch. l'

Fig. 5 is an end view artly in section, on the line V--V Fig. 1,100 ing to the right.

In the views 5 designates an ordinary electric motor, the shaft 6 of which transmits its power through a suitable mechanism including a brake-whee17 to a hoist sheave 8 engaging the hoisting chain 9 having a load engaging hook 10.

The power translating means can be of the kind illustrated in the United States patent to A. H. Chappelka, No'. 1,729,262, Sept. 24, 1929. The gear wheel of the mechanism Fig. 2 of the patent is shown by the same character in Fig. 2 in the present drawings.

rl`he character 11 designates a box containing a drum type reversing switch of ordinary construction for the electric motor and also a make and break for the motor circuit, there being suitable wiring (not shown) between the switch box, the source of power and the motor. The operation of the reversing switch is manually controlled by a shaft on the end of which is wheel 13 operated by the pull cords 33, 33; and the motor circuit cutout is automatically operated by a crank 14 when the upper and lower limits of travel of the hook 10 are approached. Mounted in suitable bearings under the frame carrying the motor and switch box is a control shaft 15 having secured to it at the end: nearer the switch box a crank 16, and connecting said crank arm 16 and the cut out crank 14 is a rod 17.

The frame 29, which isl actuated by the hoisting cable 9, at the limit of the up and down travel, automatically opens the motor circuit by the operation of the rod 17 connected with the arms 14 and 16 and the latter is fixed on the control shaft 15 to which the frame 29 is also attached. The pulling` of the cord 33 in closing the circuit also tilts the frame 29 into inclined position to be actuated by the cable 9 when the latter reaches the limit of its travel, either up or down as hereinafter described.

The reversing switch, which is of ordinary construction, includes the shaft 35 carrying suitable contacts 36 that make contacts with upper ends anchored on pins 20, 20, secured in a hood inclosing the brake. The lower ends of the brake straps are connected by toggle bars 21, 21, pivoted to brackets 22, 22, on the straps and to each other at 23. The

brake straps are actuated to apply them to the brake wheel 7 by the pressure of a coiled spring 24 transmitted to the toggle bars 21, 21, said spring mounted on a headed and threaded bolt 25, the latter being passed loose,-

ly through holes in the brackets 22, and attached to the housing by adjustable nuts 26 and 27. The cam 18 on the shaft 15 presses upward on the toggles and tends to hold thc brake straps released from the brake wheel 7, when a load is being raised.

The shaft 15 has secured to it an ellipsoidal open frame 29 having loops at its ends (see Fig. l) through the forward loop of which the load carrying chain rises and descends,

30 and the load engaging hook is provided with a cross pin 30 adapted to engage the lower side of the forward loop and raise the frame 29 to horizontal position.

One part of the hoisting chain 9 passes through the other or rear loop of the frame 29 and said chain is made of such length that when the hook 10 descends to the lower limit of its travel the loop of thechain actuates said frame to place it in horizontal position as shown by full lines Fig. 3. The horizontal position can be conveniently termed the neutral position because when in that position the power operating circuit is cut off.

The operation is this: Let it be assumed that the frame 29V is downwardly and for-.

wardly inclined as shown by broken lines Fig. 3 and the motor operating circuit closed to raise hook 10 and a load thereon. In this case when the pin 30 of the hook engages the frame 29 it elevates it to the full line position or horizontal position thereby cutting off the motor circuit y the operation of rod 17. In this position of said frame 29 cam 18 is in a position leaving the brake bands applied by spring 24.

To lower the hook 10 the motor circuit is reversed by drawing down the proper pull cord 33 and in doing this the frame 29 is at. the same time and by said pull chain through rod 17 thrown to tilted' position rearward and downwardly'as shown by broken lines Fig. 3, ready to be operated by the loop of the cable 9 when the hook 10 is sent downward and approaches the lower limit of its travel.

When the loop of the chain cable 9 rises and engages the rear loop of frame 29 that frame is again carried to horizontal or neutral position and the cam 18 returned to the posltion shown in Fig. 4, the brake being applied by spring 24 and the motor circuit cut oi by the rocking of shaft 15 and therefore movement of the rod 17. It should be noted at this point that during the lowering of the hook 10 the brake was constantly applied by the spring 24 because the cam 18 was out of position to hold the toggles 21 in elevated or brake releasing position. Remembering that the hook 10 has been lowered to the lower limit of its travel to be loaded and raised the motor circuit is again reversed by pulling down the other pull `chain 33 and the frame 29 tilted through rod 17 with its rear end down as shown by broken lines Fig. 3. When the frame 29 is thus tilted the cam 13 presses up the toggles 21 thereby releasing the brake straps and holding them released until the frame 29 is raised to neutral position by the pin 30 of the hook 10 at which time the motor circuit is cut out and the cam 18 is put into the position shown in Fig. 4 to cause an application of the brake straps by spring 24 said straps remaining applied during the descent of the hook. After this the described operations 'are repeated.

It follows from the described mechanism and its operation that the brake is'released when the load is being lifted and applied when the load carrying end of the cable is lowered. This prevents the motor from rao- ,ing when the load carrying hook is going down and relieves the motor of braking effect when the load is being raised.

The forms of the parts can be changed without departing from the gist of the invention as claimed.

What I claim is:

l. In an electrically operated hoisting apparatus, including a cable hoist, a motor and circuit therefor, a cut out for the circuit, and a brake for the motor, means operated by the cable when it approaches the upward and downward limits of its travel to cut out the motor circuit and cause the application of the brake upon the downward travel of the cable.

2. In an electrically operated hoisting apparatus, including a cable hoist, a motor and circuit therefor, a cut out for the circuit, and a brake for the motor, means operated bythe cable when it approaches the upward and downward limits of its travel to cut out the motor circuit and cause the application of the brake upon the downward travel of the cable, and manually operated means for subsequently reversing the motor circuit.

3. In an electrically operated hoisting apparatus including a cable hoist, a motor and circuit therefor, and a brake for the motor, means operated byl the cable when it apf proaches the upward and downwardlimits of the travel of its load carrying end to cut out the motor circuit, and means whereby the brake is automatically applied when said load-carrying end of the cable descends.

4. In an electrically operated hoisting apparatus including a hoisting cable having one end secured and its other end free and forming a loop, a cable driving motor and circuit therefor, a reversing switch for the circuit. a brake means for 'the motor and a cut-out for the motor circuit, a rock shaft for actuating the cut-out and brake means operated by the free end of the cable when the cable approaches the upper limit of its travel to actuate the cut-out and permit an actuation of the brake means, said rock shaft being adapted to be actuated by the loop of the cable when the free end of the cable approaches the lower limit of its travel to actuate the motor circuit cut-out and permit application of the brake, and manual means for actuating the reversing switch subsequent to operation of said cut-out.

5. In an electrically operated hoisting apparatus including a hoisting cable having one end secured and its other end free and forming a loop, a cable driving motor and circuit therefor, a reversing switch for the circuit, a brake means for the motor and a cut-out for the motor circuit, a rock shaft for actuating the cut-out and brake means operated by therfree end of the cable when the cable approaches the upper limit of its travel to actuate the cut-out and permit an actuation of the brake means, said rock shaft being adapted to be actuated by the loop of the cable when the free end of the cable approaches the lower limit of its travel to actuate the motor circuit cut-out and permit application of the brake, and manual means for actuating the reversing switch subsequent to operation of said cut-out, said manual means being actuatable to move said rock shaft to cause an application of the brake during the descent of the free end of the cable toward the lower limit of its travel.

6. In an electrically operated hoisting apparatus, including a motor circuit cut-out and reversing switch, a spring actuated brake for arresting momentum of the motor when the power circuit is opened, means actuated by the load-carrying -member to automatically open the motor circuit and apply braking force to the power mechanism when the load carrying member approaches the limit of its descending travehsaid means including a rock shaft actuated by the load carrying member, said shaft having means for actuating the circuit cut-out and means whereby said brake is released for operation during the descent of the load carrying member.

7 In an electrically operated hoisting apparatus, including a motor circuit reversing switch, a spring actuated brake for arresting the momentum of the motor when the power tuated by the load carrying member, said shaft having means for actuating an electric switch and means releasing the brake for actuation of its spring.

8. In an electrically operated hoisting apparatus, means actuated by the load carrying member to automatically cut off the power and apply braking means to the power mechanism when the load carrying member approaches the limit of its upward travel, said means including a rock shaft carrying a cross frame actuated by the load carrying member near both limits of its movement, said shaft having means for actuating an electrical circuit breaker and also means for causing the application of the brake to the power mechanism at one limit of the movement of the load carrying element.

9. In a power operated hoisting apparatus, means actuated by the load carrying member to automatically cut olf the power and apply braking means to the power mechanism when the load carrying member approaches the limit of its upward travel. and means for reversing the operation of the'power mechanism and applying the brake when the load carrying member descends to the lower limit of its travel.

10. Means for causing the application and release of a brake of a hoisting apparatus having a load hoisting cable, said means consisting of a rocking member actuated by the cable at its approaches to the upper and lower limits of its travel, and means actuated by said rocking member to permit the application of the brake at one of said approaches and leave the same released at the other of said approaches.

11. Means for causing the application and release of a brake of a hoisting apparatus having a load hoisting cable, said means consisting of a rocking member actuated by the cable at its approaches to the upper and lower limits of its travel, and means actuated by said rocking member to permit the application of the brake at the upper of said aproaches and leave the same released at the ower of said approaches.

FRANK E. STAHL. 

